Need to secure a portable toilet in a conversion van

Sorry I don't have a solution for you but I can give some advice.If it's not too late,cancel the order and order a Thetford curve.The reviews I read about this unit state that men will have a problem when sitting due to no room in the bowl for their privates.I went through this with my last van.Bought the cheaper model and gave it away.Bought the Curve and was so happy.Much more like a real toilet.